Air fresheners or space deodorants have come into increasing use in the household market in recent years. Their sales and use have increased rapidly and represent a substantial market. Such products usually consist of liquid, aerosol, or more generally, a semi-solid composition comprising various oils and other components packaged in a container provided with openings to expose the fragrance composition to the atmosphere. The fragrance components volatilize into the atmosphere to mask or otherwise decrease the perception of malodor that may be present therein.
Almost invariably the freshener compositions are comprised of volatile materials that lend a distinct fragrance of their own to the atmospheric environment. While the fragrances preferred by consumers change from time to time they usually fall into categories such as those of "floral scents", "citrus scents", "pine scents", and "herbal scents" and other less distinct groupings referred to as "fantasies". All such scents impart their own distinct fragrance to the atmosphere and all rely upon a number of theoretical mutually operative mechanisms to lower the perceived strength of malodor.
Since all such fragrances rely upon these effects, they are only effective to the extent that they volatilize efficiently to impart a significant amount of active material to the atmosphere to combat malodors present in their vicinity. While such compositions at the present state of the art, are quite effective in producing a high or adequate level of active volatile material in the atmosphere when new and fresh, they usually rapidly lose their potency, or are so volatile that the active materials are completely evaporated within a short period of time, say within a few days when continuously exposed to the ambient atmosphere.
It is therefore of interest to produce compositions that retain their effectiveness over longer periods of time whereby space deodorants may have an extended effective life and the resultant economic benefit will be realized by the consumer.
In the past, efforts to solve this problem have resorted to compositions utilizing less volatile fragrances, or formulations wherein the fragrances tend to be relatively "immobilized". In the first instance, the less volatile fragrances may be so non-volatile as to fail to produce an effective level of fragrance or active material in the ambient atmosphere. In the second instance, resort is often made to solid or semi-solid gels or similar formulations which reduce the volatility of the active components by requiring that they migrate through the mass of the gel or semi-solid toward its atmospheric interface prior to volatilization, thereby increasing the active life of the composition. Such solid or semi-solid compositions, however, are tedious to formulate; requiring mixing, heating, pouring into molds, or otherwise forming the gels and semi-solids, so that the active components are effectively volatile without being too tightly bound within the formulation such that their activity is unduly depressed. In the case of aqueous alginate and carrageenan based gels, the unsightly shrinkage over a period of time of the semi-solids thus produced is, in practice, impossible to avoid.
It will become obvious to one skilled in the art that the above disadvantages are avoided by use of the present invention.